One of the most important components in any electrical grid work is the drop out fuse. Otherwise known as the swing out fuse, this helps protect the transformers in the network from overloads. This kind of fuse is particularly useful when the transformer is in remote locations.
Advantage of the drop out fuse
The primary advantage of Polymer drop out fuses is the way a blown fuse is visible from a distance. Locating a fuse that is blown is a tedious procedure otherwise. The drop out fuses has a single point of contact at the bottom. They are vertically mounted with the fuse element holding them up on the top side. When the fuse element is blown, the fuse carrier hangs down from the unit. This is visible even from quite some distance away.
Any over current in the customer or transformer circuit will melt the fuse element opening the circuit and stopping further flow of current. You can remake the circuit by lifting out the fuse carrier using an insulated operating rod. Put the fuse element back into place. Swing the fuse carrier back to the original position. The circuit is now operational.
Different part of the fuse
The components of the cut-out fuse comprise the fuse element, the fuse holder, and the cut-out body. You can replace the fuse element or the fuse link. This portion of the assembly will melt when the current in the wire exceeds some specific value. The fuse element normally consists of alloy wires made from tin or silver. Depending on the rating the wires are made thin or thick and they will melt when the current reaches the appropriate value.
They mount the cut outs 20 degrees of the vertical so that the fuse unit will fall under its own weight when the fuse blows. During normal use, the fuse link is held up by an ejector spring in the upright position. When the fuse blows, the spring pulls the fuse link out of position reducing the surge duration. This will prevent any arc in the fuse holder. Thus, damage in the transformer and the fuse holder is eliminated.
Replacing the fuse
It is possible to manually open the fuse by a linesman standing on the ground or operating from a bucket truck. He uses a hook at the end of a fibreglass stick. With this, he can engage the pull ring that is present in the fuse holder. The standard cut-out is not designed for opening manually while there is a load in the circuit. It is possible to switch the circuit or to reload the fuse once it is blown.
The fuse holder is the portion that holds the fuse. This is an insulting tube called the door. The fuse holder drops out maintaining only bottom contact when the fuse is blown. The cut-out body is the C-shaped frame that supports the fuse holder and the insulator made of porcelain or polymer. This isolates the conductive portions of the assembly from the support structure.
The drop out fuse thus protects the equipment and people from danger. They make different fuses to varying specifications according the need and application.